generate-conda-packages: Fix typo in rm command

.github/workflows/generate-conda-packages.yaml

@@ -162,7 +162,7 @@ jobs:
             cat */bld.bat
             cat */build.sh
             # Do not generate walking-controllers, workaround for https://github.com/robotology/robotology-superbuild/issues/1572#issuecomment-1912146946
-            rm walking-controllers
+            rm -rf walking-controllers
             # We use the conda_build_config from conda-forge-pinning, and our local one
             # See https://docs.conda.io/projects/conda-build/en/latest/resources/variants.html#creating-conda-build-variant-config-files
             # We manually specify the build order as conda build is too slow, and conda mambabuild does not support correctly multiple recipes